[HamWAN PSDR] HamWAN via passive reflectors

[Bart Kus]

Hello,

Today I participated in a HamWAN field test for the upcoming Field Day 
event @ Luther Burbank park.  During the testing, a couple very 
interesting working RF paths surfaced.  Here is the most impressive one:



We had setup a dish at the northern tip of Luther Burbank Park, and 
aimed it at downtown Seattle (around Columbia Tower).  We picked up a 
signal from Baldi-S1!  The measured distance (time of flight 
measurement) was 67km.  This means the RF was bouncing off of downtown 
Seattle and heading all the way out to Baldi by Enumclaw! The data 
throughput measured was about 1.2Mbit each way average, peaking at 1.5Mbit.

We moved the dish atop the hill at the park, pointed it at Baldi through 
a narrow opening in the closer hill ridges, and did a follow-up test.  
The measured distance (time of flight measurement) in that direct test 
was 56km: an 11km difference!  The measures aren't very accurate, so the 
3km error compared to real physical distance is within the expected 
error range.  Keep in mind that 3km is only 10 microseconds in terms of 
RF signal flight.

Feeling inspired by this astounding Baldi result, we decided to test a 
reflected RF path to the Capitol Park cell site:



We pointed the dish at a random hillside across the water from Luther 
Burbank, and picked up Capitol Park @ up to -73dBm.  Bouncing off this 
hillside we got 3.5Mbit download and 5Mbit upload speeds to the Internet.

I guess the lesson here is: If you don't have a direct path to a HamWAN 
cell site, perhaps you can try playing with some indirect reflected 
paths to get connected!

--Bart

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